Deflection control means for machine housings

ABSTRACT

The housing is divided at an intermediate point and a ring having two mating annular parts is positioned between the divided housing parts. The mating parts of the ring are rotatable about a common axis and are of varying thickness so that relative rotation of the mating parts causes an increase or decrease in the amount of sag or deflection of the housing at that point. The difference in deadweight sag between the rotor and the housing can thus be held to a minimum.

United States Patent [1 1 Zerlauth DEFLECTION CONTROL MEANS FOR MACHINE HOUSINGS [75] Inventor: Ferdinand Zerlauth,Andelfingen,

Switzerland [73] Assignee: Brown Boveri-Sulzer Turbomachinery, Limited, Zurich, Switzerland [22] Filed: Feb. 18, 1972 [21] App]. No.: 227,431

[30] Foreign Application Priority Data Mar. 17, 1971 Switzerland ..44l7l7l [52] U.S. Cl 415/134, 415/219, 60/3931 [51] Int. Cl. F0ld 25/28, F02c 7/20 [58] Field of Search 415/134, 219 R;

[5 6] References Cited UNITED STATES PATENTS 3,556,672 1/1971 Gentile 60/3931 June 19, 1973 Trassel et al 415/134 Guillot 415/134 FOREIGN PATENTS OR APPLICATIONS 927,782 5/1955 Germany. 415/219 Primary Examiner Hen ry F. Raduazo Attorncy- Hugh A. Chapin and Francis C. Hand [57] ABSTRACT The housing is divided at an intermediate point and a ring having two mating annular parts is positioned between the divided housing parts. The mating parts of thering are rotatable about a common axis and are of varying thickness so that relative rotation of the mating parts causes an increase or decrease in the amount of sag or deflection of the housing at that point. The difference in deadweight sag between the rotor and the housing can thus be held to a minimum.

4 Claims, 4 Drawing Figures Patented June 19, 1973 3,740,164

3 Sheets-Sheet 1 3 Sheets-Sheet 2 mm mm R NM QM QN 3 w vm RN um MN mm mm mm Patented June 19, 1973 3 Sheets-Sheet 5 DEFLECTION CONTROL MEANS FOR MACHINE HOUSINGS This invention relates to a deflection control means for machine housings, and particularly, for machine housings subject to elastic deformation under deadweight.

Heretofore, it has been known that the sag due to the deadweight of machine housings and rotors therein has been very considerable. However, any rotor play relative to the housing must be made as small as possible, particularly in the case of turbines and compressors for gaseous working media, in order to keep clearance losses low. The same considerations apply to hydraulic machinery. As it has only been in the rare cases that the sag at the housing has been the same as the sag at the rotor, it has been necessary to increase the clearance between the rotor and housing by increasing the inside diameter of the housing by an amount equivalent to the difference between the sags in order to prevent the rotor from brushing against the housing. This, however, results in increased clearance losses.

Accordingly, it is an object of the invention to use as small a clearance as possible between a housing and a rotor mounted within the housing.

It is another object of the invention to minimize the difference in sag due to deadweight between a rotor and a housing.

It is another object of the invention to provide a simple relatively inexpensive means of minimizing differences in sag between two concentrically mounted members.

Briefly, the invention provides a ring made of two part-rings which bear on one another and which are inserted at a junction between two housing portions.

The plane of division between the two part-rings is inclined in relation to the contact planes directed towards the housing sections or portions so that the contact planes can be adjusted relative to one another to a selective angle by turning the part-rings in relation to one another. As the part-rings can be suitably turned in relation to one another, the differences between the housing axis flexure clue to deadweight and the rotor axis flexure due to deadweight can be kept at a minimum. In this way, it is possible to maintain a minimum clearance between the rotor and housing. Of course, the rings can also be used to correct any machining errors at the places where the housing sections come together, for example, at the flanges.

Each of the part-rings can be divided two or more times about the periphery so as to form arcuate segments. In addition, the ring parts can be secured in place and retained in any suitable fashion such as by releaseable straps.

These and other objects and advantages of the invention will become more apparent from thefollowing detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a longitudinal sectional view of a part of a machine housing utilizing a ring according to the invention;

FIG. 2 illustrates a detail of the ring of FIG. I to an enlarged scale;

FIG. 3 illustrates a partial longitudinal sectional view of a gas-turbine unit incorporating a ring therein according to the invention; and

FIG. 4 illustrates a view of an exhaust gas turbine supercharger unit for internal combustion engines utilizing a ring according to the invention.

Referring to FIG. 1, two housingparts l and 2 of a machine are interconnected by means of flanges 3 and 4 each of which is perpendicular to the machine axis 5. An intermediate ring 6 is inserted between these flanges 3, 4 and consists of two part-rings 7 and 8. The

plane of contact between these part-rings 7 and 8 is inclined in relation to the planes of contact of the ring 6 with the flanges 3 and 4 of the machine housing parts 1, 2. In addition, the flanges 3, 4 and the part-rings 7, 8 have bores 9 (FIG. 2) which are spaced at a uniform pitch t over the periphery of a pitch circle 10.

The inclination of the flanges 3, 4 of the housing parts 1, 2 in relation to one another are adjusted by turning the part-rings 7, 8 on the pitch circle 10 so that the flexure of the housing axis 5 due to the deadweight can be changed, either by increasing or by decreasing the degree of flexure. In this way, the difference between the flexure of the housing axis 5 due to deadweight and the flexure of the axis of a rotor (not shown) surrounded by the housing can be adjusted to approach a minimum value. This adjustment can'be carried out on assembly and needs no further modification as operation progresses, since experience has shown that there are practically no further changes in the housing, for example, due to material creep. If, however, considerable variations occur in subsequent operation, the housing can be supported and the bolts removed and then the rings 7, 8 can be displaced in relation to one another so that in the: renewed state of the material the minimum dimension of the difference in flexure between the housing and the rotor 6 is restored to a minimum value. In order to facilitate such corrections, it is adviseable to make the part-rings 7 and 8 in two parts and to interconnect the ring halves by detachable straps 11 and 12 as shown. The connection of the straps ll, 12 to the part-ring halves is made, for example, by means of screw bolts 13 with countersunk heads.

Referring to FIG. 3, a gas turbine plant comprises a gas turbine 20 and a compressor 21. Air for combustion is drawn from a feed duct 22 by the compressor 21 and delivered in the compressed state through a duct 23 to combustion chambers (not shown) disposed around the gas turbine 20. The combustion gas flows through a duct 24 into the gas turbine blading and then through a duct 25 to an exhaust gas housing 26 of the machine as is known. In addition, a compressor rotor 27 and a turbine rotor 28 are constructed as an integral member which is supported in bearings 29 and 30. The turbine housing is made up ofindividual sections 31, 32 and 33. The compressor housing may also be made up of a number of sections, one of which, 34, can be seen at the compressor and adjacent the turbine. The housing sections 31 to 34 provide a tubular housing which is supported on a base plate 37 by suitable support members 35 and 36. These support members 35, 36 are disposed substantially in the central planes 38 and 39 of the bearings 29 and 30. Between these bearings 29, 30, both the housing 31 34 and rotor 2728 experience flexure corresponding to gravity, the axes of flexure having considerable differences in practice in every case.

In order to make the flexural axes of the rotor 27-28 and housing 31-34 coincide as far as possible, a ring 6,

as described above and illustrated in FIGS. 1 and 2, consisting of two halves, is inserted between flanges of the housing sections 33 and 34. The housing flexure is adapted to the rotor flexure by turning the halves of this ring 6 suitably in relation to one another, so that the different flexures are brought to a minimum at every part of the machine length. In most cases, it will be necessary to increase the housing flexure by means of this ring 6 because the natural flexure of the housing 3l34 is less than that of the rotor 27-28.

Referring to FIG. 4, an exhaust gas turbine supercharger unit has a rotor 40 disposed inside a housing made up of sections 41, 42, 43 and 44. In the middle region, this housing is supported by the claws 45 of a bracket 46 of an internal combustion engine (not shown). In addition, the housing section 41 supports a bearing 47 and the housing section 44 supports a bearing 48. The housing 41-44 is thus bent downwards at the ends by the deadweight and, more particularly, by the bearing loading, so that the housing axis appears to be bent upwards while the rotor 40 mounted at the two ends thereof is bent downwards. Consequently, the seals in the middle of the rotor 40 and at the turbine and compressor rotors are subject to considerable displacements in relation to the housing surrounding these parts. In order to obviate this disadvantage, a ring 6 as described above and as shown in FIGS. 1 and 2 is incorporated at least between the flanges of the housing sections 42 and 43. The gap between the compressor rotor 49 and the stationary cover disc 50 can thus be ad justed to a minimum value by adjustment of the optimum wedge angle for the ring 6 so that efficiency can be increased accordingly by reduction of the gap. If the turbine rotor 51 also experiences excessive displacemen ts in relation to the housing, a similar double ring could also be incorporated between the flanges of the housing parts 43 and 44. An improvement of operating efficiency can then be obtained at least at the blade ends by gap reduction.

In the case of the machine shown in FIG. 4, the insertion of the rings also provides for a reverse flexure of the housing. That is, the housing, which is bent downwards at the ends solely by the influence of gravity, can be bent by the intermediate ring 6 so that the ends are conversely raised above the geometric axis.

The invention thus provides a simple and relatively inexpensive means for controlling the sag or deflection in a machine housing. In this respect, the double ring can be simply made and put in place in a simple manner. The two parts of the ring are of varying thickness as shown in the drawings and can be made from identical pieces. Such pieces can be initially disposed in mating engagement with each other to form a single minimal thickness with the plane of the contact surfaces therebetween disposed at an angle to the plane of the exposed surfaces which are parallel to each other. Rotation of one ring with respect to the other causes the exposed planes to move from a parallel position to a position in which the planes are angularly disposed with respect to each other.

What is claimed is:

1. In combination with a machine housing having a pair of separately supported sections disposed about a longitudinal axis;

a ring disposed between said sections for changing the deflection of said sections from said axis in the plane of said ring, said ring comprising a pair of part-rings in bearing relation to each other and to a respective one of said housing sections, said partrings being of varying thickness to dispose the plane of division therebetween at an inclined angle relative to the contact planes thereof whereby the contact planes between each part ring and housing section can be adjusted relative to each other to a selective angle upon rotation of at least one of said rings.

2. The combination as set forth in claim 1 wherein each housing section includes a flange thereon bearing against a respective part ring, each said flange and each said part ring having a plurality of circumferentially spaced bores therein disposed about a pitch circle with uniform pitch to receive bolts for securing said sections and part-rings together.

3. The combination as set forth in claim 1 wherein each part-ring is divided into at least two annular segments.

4. The combination as set forth in claim 3 which further includes a releaseable strap securing each pair of adjacent segments together. 

1. In combination with a machine housing having a pair of separately supported sections disposed about a longitudinal axis; a ring disposed between said sections for changing the deflection of said sections from said axis in the plane of said ring, said ring comprising a pair of part-rings in bearing relation to each other and to a respective one of said housing sections, said part-rings being of varying thickness to dispose the plane of division therebetween at an inclined angle relative to the contact planes thereof whereby the contact planes between each part ring and housing section can be adjusted relative to each other to a selective angle upon rotation of at least one of said rings.
 2. The combination as set forth in claim 1 wherein each housing section includes a flange thereon bearing against a respective part ring, each said flange and each said part ring having a plurality of circumferentially spaced bores therein disposed about a pitch circle with uniform pitch to receive bolts for securing said sections and part-rings together.
 3. The combination as set forTh in claim 1 wherein each part-ring is divided into at least two annular segments.
 4. The combination as set forth in claim 3 which further includes a releaseable strap securing each pair of adjacent segments together. 